cleanup and docs

Author: yottatsa

README.md

@@ -1,6 +1,19 @@
 # 80188 single board modular computer
 
-v.0.1.0
+* testing and firmware development: r1
+* hardware development: r2
+
+## Configuration
+
+* 8MHz 8086-compatible CPU
+* 128KB low SRAM
+* 256KB EEPROM (27C020) or Flash (SST39SF020) with in-system programming and software programming capabilities
+* PC/104-compatible with 8-bit ISA bus
+  - 80188 Timer A is routed to OSC
+* Dual channel 16550-compatible UART
+  - FTDI USB-Serial/6-pin connector on port A
+  - 5V 9pin connector on port B
+* AT-compatible RTC
 
 ## References
 * [Tandy 2000 BIOS](https://www.retrotronics.org/svn/t2kbios/)
@@ -9,11 +22,17 @@ v.0.1.0
 
 ## Notes
 
-### 0.1.0r1
+### r1
 
 * minor: SYSBUS socket is too close to the CPU socket and can'tbe used with the wide connector
 * minor: 16V8 /OE and GND pin names were swapped
 * minor: UART1 labels are wrong
 * major: 74x573 OE should be /OE
 * major: 16V8 /RESET can't be used as input
+* major: PLCC sockets are unreliable
 * unknown: 22V10 Verification failed at address 0x16C5: File=0x01, Device=0x00
+* feature: added in-system programming
+* major: 39x flash doesn't work as /PGM is floating
+
+### r0
+* major: PCB socket is unreliable

fw/8250.S

@@ -100,7 +100,7 @@ _serial_puts:
 %macro	_serial_puts 1
 		mov	bx, %1
 %%loop:
-		mov	al,[ds:bx]
+		mov	al, [ds:bx]
 		cmp	al, 0
 		jz	%%end
 		mov	cl, al

fw/Makefile

@@ -1,4 +1,7 @@
 sources = reset.S monitor.S
+targets = fw.bin debug.txt
+
+all: $(targets)
 
 # firmware
 fw.bin: $(sources:.S=) 
@@ -14,16 +17,19 @@ reset.sym: reset
 	grep -f reset.glob reset.map | \
 		awk 'BEGIN{print ";; autogenerated"}{print $$3,"equ","0x"$$1}' > $@
 
+debug.txt: reset
+	grep -e '^\s*say_what' -e '^[a-z_\.]*:$$' reset.S > $@
+
 # assembly
 %: %.S
 	nasm $< -o $@
 
 clean:
-	rm -f fw.bin $(sources:.S=.d) $(sources:.S=) reset.o reset.glob reset.map
+	rm -f $(targets) $(sources:.S=.d) $(sources:.S=) reset.o reset.glob reset.map
 
 # deps
 %.d: %.S
 	nasm -M $^ > $@
 include $(sources:.S=.d)
 
-.PHONY: clean
+.PHONY: all clean

fw/debug.txt

@@ -0,0 +1,37 @@
+_mon:
+_putch:
+_getch:
+_setup:
+		say_what 0xb007		; jumped to the setup code
+		say_what 0xb105
+_soc_failure:
+		say_what 0xdead
+_soc_passed:
+		say_what 0xc0de
+_set_mem:
+_set_pcs:
+_test_setup_rom:
+.loop:
+.check:
+.rom_failure:
+		say_what 0x0bad
+.end:
+		say_what bx		; checksum
+		say_what 0x1337		; rom check passed
+_set_sp:
+		say_what ss		; 0x1000
+		say_what sp		; 0xffff
+_test_ram_words:
+		say_what si		; ram test address
+		say_what cx		; ram test value to write
+		say_what bx		; ram test value readback
+.ram_failure:
+.halt:
+		say_what 0x2bad
+.end:
+		say_what 0xcafe		; memory test passed
+_init_serial:
+_print_version:
+.loop:
+_finish:
+_restart:

fw/fw.bin

@@ -9,9 +9,7 @@ segment .text		start=0xc0000	align=256
 ; 256k flash monitor entry point
 _mon:
 	jmp	_mon
-
 _echo:
 	call	0xf000:(_getch & 0xffff)
-	mov	cx,ax
 	call	0xf000:(_putch & 0xffff)
 	jmp	_echo

fw/monitor.S

@@ -20,16 +20,33 @@ GLOBAL UMCS, LMCS, PACS, MMCS, MPCS, MAXRAM, _restart, _putch, _getch, _version
 %include "amd80c188.inc"
 %include "platform.inc"
 
-; uncomment for the full ram image
-;		org	0x0
 
-
-segment .text		start=0xc0000	align=256
+segment .stub		start=0xc0000	align=256
 ; 256k flash monitor stub
 _mon:
 		jmp	_mon
 
 
+segment .text		start=0xf0000	align=256
+; BIOS functions
+_putch:
+;; write the content of BL over serial, blocking
+		push	ax
+		push	dx
+
+		_serial_putch bx
+
+		pop	dx
+		pop	ax
+		retf
+
+_getch:
+		push	dx
+		pop	dx
+		retf
+
+
+
 segment .data		start=0xffc00	align=256
 ; platform constants in ROM space
 ; useful to read/change parameters
@@ -41,12 +58,11 @@ MMCS:		dw	0x0000 		; not handled yet
 MPCS:		dw	MPCS_DEF
 MAXRAM:		dw	0x80		; in KB
 
+
 segment .setup		start=0xffd00	progbits
 ; main setup code
-
 _setup:
-		;; entry point
-		say_what 0xb007
+		say_what 0xb007		; jumped to the setup code
 
 
 		;; proper init
@@ -79,39 +95,22 @@ _soc_passed:
 		say_what 0xc0de
 
 _set_mem:
-		mov	ax,0xf000
-		mov	ds,ax
-		mov	dx,UMCS_REG
-		mov	ax,[ds:UMCS]
-		out	dx,ax
-		mov	dx,LMCS_REG
-		mov	ax,[ds:LMCS]
-		out	dx,ax
+		mov	ax, 0xf000
+		mov	ds, ax
+		mov	dx, UMCS_REG
+		mov	ax, [ds:UMCS]
+		out	dx, ax
+		mov	dx, LMCS_REG
+		mov	ax, [ds:LMCS]
+		out	dx, ax
 
 _set_pcs:
-		mov	dx,PACS_REG
-		mov	ax,[ds:PACS]
-		out	dx,ax
-		mov	dx,MPCS_REG
-		mov	ax,[ds:MPCS]
-		out	dx,ax
-
-;_set_sp:
-;		;; ss = (((0x80 - 1) >> 6) << 12)
-;		;; sp = (0x80 << 10) - 1
-;		mov	ax, [ds:MAXRAM]
-;		dec	ax
-;		shr	ax, 6
-;		shl	ax, 12
-;		mov	ss, ax
-;
-;		mov	ax, [ds:MAXRAM]
-;		shl	ax, 10
-;		dec	ax
-;		mov	sp, ax
-;
-;		say_what 0x1337
-
+		mov	dx, PACS_REG
+		mov	ax, [ds:PACS]
+		out	dx, ax
+		mov	dx, MPCS_REG
+		mov	ax, [ds:MPCS]
+		out	dx, ax
 
 _test_setup_rom:
 		mov	si, 0xfd00
@@ -123,32 +122,47 @@ _test_setup_rom:
 		inc	si
 		loop	.loop
 .check:
-		mov	ax,[ds:SETUPSUM16]
+		mov	ax, [ds:SETUPSUM16]
 		cmp	ax, bx
 		jne	.rom_failure
 		jmp	.end
 .rom_failure:
 		say_what 0x0bad
 		jmp	.rom_failure
 .end:
-		say_what bx
-		say_what 0x1337
+		say_what bx		; checksum
+		say_what 0x1337		; rom check passed
+
+
+_set_sp:
+		;; ss = (((0x80 - 1) >> 6) << 12)
+		;; sp = (0x80 << 10) - 1
+		mov	ax, [ds:MAXRAM]
+		dec	ax
+		shr	ax, 6
+		shl	ax, 12
+		mov	ss, ax
+		say_what ss		; 0x1000
+
+		mov	ax, [ds:MAXRAM]
+		shl	ax, 10
+		dec	ax
+		mov	sp, ax
+		say_what sp		; 0xffff
 
 
 _test_ram_words:
 		mov	ax, 0x0
 		mov	es, ax
 		mov	si, 0x1234
 		mov	cx, 0xabcd
-		say_what si
-		say_what cx
-;; went past here
-		mov	[es:si],cx
-		mov	[es:si],cx
-		mov	bx,0x0
-		mov	bx,[es:si]
+		say_what si		; ram test address
+		say_what cx		; ram test value to write
+		mov	[es:si], cx
+		mov	bx, 0x0
+		mov	bx, [es:si]
+		say_what bx		; ram test value readback
 		cmp	bx, cx
-		say_what bx
 		jne	.ram_failure
 		jmp	.end
 
@@ -157,7 +171,7 @@ _test_ram_words:
 		say_what 0x2bad
 		jmp	.halt
 .end:
-		say_what 0xcafe
+		say_what 0xcafe		; memory test passed
 
 
 _init_serial:
@@ -166,7 +180,7 @@ _print_version:
 		mov		dx, UART_THR
 		mov		bx, _version
 .loop:
-		mov		al,[ds:bx]
+		mov		al, [ds:bx]
 		cmp		al, 0
 		jz		.end
 		out		dx, al
@@ -178,44 +192,12 @@ _print_version:
 
 _finish:
 		_serial_puts	_ok
+		sti
 		jmp	0xc000:_mon
 
 ; text constants
 
 _ok:		db	"OK",0x0a,0x0
-;_bad:		db	"failed",0x0a,0x0
-
-
-; BIOS functions
-_putch:
-;		push	ax
-;		push	dx
-;
-;		_serial_putch cx
-;
-;		pop	dx
-;		pop	ax
-;		retf
-;
-_getch:
-;		push	dx
-;
-;		mov	dx, I8251_C
-;		mov	al, 0x34	; RTS, Reset Error Flag, RX
-;		out	dx, al
-;
-;.wait_ready:	in	al, dx
-;		and	al, 0x02	; RXRDY
-;		jz	.wait_ready
-;		mov	al, 0x10	; Reset Error Flag
-;		out	dx, al
-;
-;		mov	dx,I8251_D
-;		in	al, dx
-;
-;		xor	ah, ah
-;		pop	dx
-;		retf
 
 
 segment .restart	start=0xffff0	progbits